Well, I can't say I've really done "formal" art therapy (that I know of) but "art" and creative expression have been very therapeutic for me my whole life.
There are many different concepts about "art" and the associated "aptitude". Honestly, I think we're all "artistic" to a degree, it's finding the medium, the "attitude" and means of expression that suit the individual, IMHO. Some are very good at sewing, it's a broad and very artistic means of expression. Some groove on Collage, art from an assembly of "found objects". Still other seek function; there's art in cooking, and woodworking, IMO. "Art" might be what we wear. For some, custom cars are high art. And gardening too. No fooling.
A strong connection to a creative outlet, a creative challenge with associated technical skill building, has for me been like "ballast" or a "rudder". It's getting in touch with the energy that flows through me, and channeling it in a constructive way. A way that's satisfying and helps build self-esteem. A form of action.There is probably way more to "art therapy" than I know. But "art" as a channel, sounds very healthy.